1. Field of the Invention
This invention pertains to a waste liquid disposal system and, more particularly, to such a system for cleaning carpets.
2. Description of the Related Art
Carpet cleaners that spray a detergent solution into a rug and then vacuum the dirty water out of the rug are widely used by small businesses and homeowners. The dirty water removed from the carpet contains harmful chemicals and cannot be deposited in storm drains. Instead, this dirty water must be deposited in sewer lines that eventually lead to a sewer treatment plant. Because many homes and businesses are connected to sewer lines, users often deposit the waste water directly in their toilets.
Most mug cleaners include a holding tank in which the waste water is temporarily deposited. Some cleaners, such as the one disclosed in U.S. Pat. No. 4,823,428, include sensing switches located inside the holding tank that detect when the waste water inside the holding tank is at a specific level. When the waste water reaches a specific level, it is then automatically discarded by gravity through a lower opening in the holding tank into a toilet or sewer line.
One problem with using sensing switches located inside the holding tank is that they often fail to operate when clogged or corroded. Another problem is that when the waste water is discarded from the holding tank, the vacuum pressure is temporarily lost thereby discontinuing removal of waste water from the carpet.
What is needed is an improved carpet cleaning system that automatically and continuously discards the waste water into a toilet or sewer drain without discontinuing the vacuum pressure to the cleaning apparatus.
It is an object of the present invention to provide a continuous carpet cleaning system that automatically discards collected waste water into a toilet or sewer line. It is believed that such a system that uses in combination two recovery tanks, two opposite oriented check valves, an air control valve, and a control means to control the air control valve is not anticipated, nor rendered obvious, suggested, or even implied by any prior art carpet cleaning apparatus, either alone or in any combination thereof.
The carpet cleaning system disclosed herein uses heated cleaning water pumped from a truck to a carpet cleaning apparatus via a water delivery hose. A main vacuum hose runs from the truck to an improved waste water disposal tank located directly over a toilet connected to a sewer drain or located directly over a sewer drain. A second vacuum hose connects the carpet cleaning apparatus to the disposal tank to deliver waste water from the carpet cleaning apparatus to the disposal tank. The disposal tank is designed to continuously collect waste water from the carpet cleaning apparatus and to automatically discard the waste water into the toilet or sewer drain at pre-selected time intervals or when the waste water reaches a specified level inside the disposal tank.
The disposal tank is divided into an upper primary recovery tank and a lower secondary recovery tank. Located in the primary recovery tank are a main vacuum exhaust port and a waste water inlet port. The main vacuum exhaust port connects to one end of the main vacuum hose that connects at its opposite end to a vacuum source. The waste water inlet port connects to one end of a second vacuum hose that connects at its opposite end to the carpet cleaning apparatus. When vacuum pressure is created in the primary and secondary recovery tanks, it is automatically created in the secondary vacuum hose and delivered to the carpet cleaning apparatus.
In order to automatically discard waste water from the disposal tank and continuously provide adequate vacuum pressure to the carpet cleaning apparatus, a novel combination of stacked recovery tanks, two opposite oriented valves, an air control valve, and control means are used. More specifically, disposed between the primary recovery tank and the secondary recovery tank is a first check valve. The first check valve is oriented so that it is open when equal vacuum pressure is created in the primary and secondary recovery tanks, when waste water is delivered to the primary recovery tank, it automatically drains into the secondary recover tank. Formed on the secondary recovery tank is a second check valve. The second check valve is oriented in the opposite direction as the first check valve so that it is closed when air pressure inside the secondary recovery tank is sub-atmospheric. When the first check valve closes, the second check valve opens, and vise versa.
Disposed between the primary recovery tank and the secondary recovery tank is an air conduit connected to a secondary valve port on the air control valve. The air control valve includes two valve ports with one valve port connected to the sides of the secondary recovery tank and the other valve port connected to the air conduit. The air control valve also includes an outside air port exposed to the atmosphere. During use, the air control valve controls the flow of air into the primary recovery tank from the secondary recovery tank or from the atmosphere. When the components of the system are properly connected together and the vacuum source is initially activated, the outside inlet port on the air control valve is closed so that vacuum pressure in the primary and secondary recovery tanks are equal which, in turn, causes the first check valve to automatically open. Since the pressure inside the secondary recovery tank is below atmospheric pressure, the second check valve automatically closes thereby allowing waste water to accumulate inside the secondary recovery tank.
When the air control valve is activated, the outside inlet port opens thereby enabling outside air to enter the secondary recovery tank and close the first check valve. When the air pressure inside the secondary recovery tank equals or exceeds atmospheric pressure, the second check valve opens and discharges the waste water from the secondary recovery tank. When the air control valve is deactivated, the outside inlet port closes so that the pressures inside the primary and secondary recovery tanks return to their initial state.
In the preferred embodiment, the air control valve is an electric solenoid valve connected to a control means to prevent overfilling of the secondary recovery tank. In the preferred embodiment, the control means is a timer designed to continuously open and close the solenoid valve at regular, pre-selected intervals. In a second embodiment, the timer is replaced with float switches located inside the secondary recovery tanks that automatically control the ports on the air control valves when the waste water reaches a specific level inside the secondary recovery tank. An optional control means is also provided inside the primary recovery tank to prevent overfilling of the primary recovery tank when the first check valve closes.
In another embodiment using a mobile system, a basin is provided under the secondary recovery tank to temporarily collect the discharged waste water from the secondary recovery tank. A pumping means and hose may be attached to the basin so that the discharged waste water may be transferred to a remote location.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.